Can Transistors Sound like Valves?

An objective comparison is made between a referenced high-voltage solid state preamplifier with acclaims of large signal capabilities comparable to a valve amplifier, and an ECC83 based preamplifier topology. By analyzing the interaction of individual harmonic amplitudes throughout the amplifiers overload regions it is shown that there is little correlation between the two systems signal outputs. The paper describes the properties of the valve sound as having a dominant second order harmonic with an array of higher order harmonics producing the popular warmth of distortion often used for guitar amplification. The resulting dominance of 2nd and 4th harmonic components in the solid state system suggests that the sound could well be appealing to the listener, however the presence of prevalent higher order harmonics in contrast to the attenuated higher harmonics of the
valve stage demonstrate that the two systems may sound different.